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The topic of this review is the effect of magnetic field on photo‐current (PC) in organic semiconductor devices. Magnetic field modifies the fraction of the singlet/triplet population in the charge transfer excitons (CTE) whose lifetime is spin configuration dependent yielding magneto‐PC (MPC). We review MPC in the framework of the polaron pair model and emphasize the effect of CTE lifetime on MPC. In addition to a detailed calculation of the MPC response we find a range of physical parameters in which the response follows a simple ′fit function′. For example, a sum of wide and narrow Lorentzian functions, MPC(B)=cwB2/(B2+bw2)+cnB2/(B2+bn2), in the case of hyperfine interaction; or a Voigt profile V=L*G, where the sign * stands for the convolution operation between a Lorentzian (L) and a Gaussian (G) functions, in the case of thermal spin polarization. We provide expressions for the fit parameters in terms of physical parameters.

We report the magnetic field dependence of the magneto-photocurrent (MPC) in organic light emitting diodes made of homo-polymer organic layers and compare it to the measured magneto-conductance (MC) in the same diodes. We find that the response MPC(B) is very different from MC(B) in at least two respects. (a) The low field (B < 50 mT) response of MPC(B) is narrower by a factor of ∼5 from that of MC(B). (b) At high fields (B > 4 T), MPC(B) has a stronger dependence on B, d(MPC)/dB ∼ 5d(MC)/dB. We attribute these differences to a unique feature of charge transfer excimers that are responsible for MPC: sub-ns fast fusion back to singlet excitons and slow (ns to μs) dissociation to free charges. In contrast, MC(B) is determined by long lived (>10 ns) polaron pairs having singlet and triplet dissociation rates of the same order.

The static magnetic properties of the easy plane antiferromagnet CsMnBr, were studied by meansof a three-coordinate vibratingsamplemagnetometer in fields up to75 kOe and in the temperature range 1.7-80 K. it was revealed that in some field interval, H 1 e, a magnetization component rMllc appears in the crystal. The results obtained indicate that spins deviate from the basal plane. The phase diarram corcespondin~ to this deviation is discussed.. Recently, a considerable number of theoretical and experimental studies have been devoted to the magnetic properties of the quasi-one-dimensional hexagonal antiferromagnet CsMnBr, (space group D& with lattice parameters a = 7.61 8, and c = 6.52 ,&,density D = 4.30 g ~m-~[l]).Thisinterestisgenerated,inpart, byacombination of the quasi-one-dimensionality and non-collinear magnetic structure of this antiferromagnet, which result in a non-trivial magnetic phase diagram [2].In accordance with data obtained in elastic neutron diffraction experiments [3], CsMnBr, has, for H = 0 and below the three-dimensional magnetic ordering temperature T, = 8.32 K, a stacked triangular structure with spins lying in the basal easy

Magnetic field and temperature dependence of the magneto‐conductance (MC) of thin films made of self‐p‐doped poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) having room temperature conductivity of ≈200 S cm−1 in the range of fields B = 0–14 T and temperatures T = 1.8–300 K are reported. At B = 0 and for current parallel to the film surface, the conductance follows a variable range hopping mechanism in two dimensions. It is shown that the finite Coulomb correlations, U, within the nano‐crystalline PEDOT islands dominates MC at low temperatures and high fields. At T = 1.8 K, the intra‐island Coulomb correlation spin polarization mechanism is already saturated for B > 10 T establishing a finite minimum of ≈2 meV for U. This small value of U is in line with the delocalized nature of the holes within the PEDOT islands and the relatively high conductivity that makes it essential in organic opto‐electronics.